1. Field of the Invention
The embodiments of the invention relate to a display device, and more particularly, to a liquid crystal display device and fabricating method thereof. Although embodiments of the invention are suitable for a wide scope of applications, it is particularly suitable for preventing electric short of a gate line or a data line due to static electricity.
2. Description of the Related Art
Generally, a liquid crystal display device includes a thin film transistor array substrate and a color filter substrate array that face each other along with a liquid crystal material between the two substrates. FIG. 1 is a plan view illustrating a liquid crystal display device of the related art and FIG. 2 is a cross sectional view along line I-I′ of FIG. 1. Referring to FIG. 1 and FIG. 2, a thin film transistor array substrate 10 includes gate lines (GL) and data lines (DL) crossing each other on a lower substrate 1, a thin film transistor (T) positioned adjacent to where the data lines (DL) and the gate lines (GL) cross each other, and liquid crystal cells (C) disposed in the areas defined between the crossing data lines (DL) and gate lines (GL). Each liquid crystal cell (C) includes a pixel electrode (not shown) connected to the drain electrode of the thin film transistor (T) on the thin film transistor array substrate 10, a common electrode 14 formed on the color filter array substrate 20 and a layer of liquid crystal, which is located between the pixel electrode and the common electrode 14. Driving signals are provided to the gate lines (GL) and the data lines (DL) by the driving circuit (not shown). Gate pads (GP) in the non-display area are connected to gate lines (GL) extending from the display area. Data pads (DP) in the non-display area are connected to data lines (DL) extending from the display area. The driving circuit is connected to the gate pads (GP) and the data pads (DP). The thin film transistor is turned on by a scan signal provided on the gate line (GL) so that a data signal on the data line (DL) is provided to the pixel electrode connected to the thin film transistor.
The color filter array substrate 20 has a black matrix 12 that divides the upper substrate 11 into cell areas. Color filters (not shown) are formed in the cell areas partitioned by the black matrix 12. A common electrode 14 is positioned on the color filters for forming a vertical electric field with the pixel electrode on the lower substrate 1 to drive the liquid crystal layer between the common electrode 14 and the pixel electrode.
The thin film transistor array substrate 10 has a common line (CL) to provide the standard voltage to the common electrode 14, which is formed on the color filter array substrate 20 in the non-display area outside of the display area. The common line (CL) is formed in an area in which a conductive sealant 26 is coated onto the color filter array substrate 20. The conductive sealant 26 joins the thin film transistor array substrate 10 to the color filter array substrate 20. The common line (CL) is electrically connected to the common electrode 14 of the color filter array substrate 20 through conductive balls 25 in the conductive sealant 26. More specifically, the common line (CL) includes a common line lower electrode 7 formed in the same layer as the gate line (GL) on the lower substrate 1 and a common line upper electrode 8 contacting the conductive ball 25. A common contact hole 9 in a gate insulating layer 4 and a passivation layer 6 exposes the common line lower electrode 7. The common line upper electrode 8 contacts the common line lower electrode 7 through the common contact hole 9. The conductive ball 25 is formed of a highly conductive metal, such as Au.
The conductive ball 25, which connects the common line (CL) and the common electrode 14 electrically, are disposed throughout the entire area in which the conductive sealant 26 is coated onto the color filter array substrate 20. In other words, the conductive balls 25 are positioned in to overlap areas where the data lines (DL) or the gate lines (GL, refer to FIG. 1) are formed, as shown in FIG. 2.
The passivation layer 6 of the liquid crystal display device can be destroyed due to static electricity occurring on the LCD. FIG. 3 is an illustration of a short between the data line and the common electrode due to an insulating layer being broken by static electricity. If the passivation layer 6 is broken where a conductive ball 25 overlaps a data line (DL), the data line (DL) and the common electrode 14 can be electrically shorted to each other by the conductive ball 25, as shown in FIG. 3. Such a defect, decreases production yield. Further, if the passivation layer 6 and the gate insulation layer 4 are both broken where a conductive ball 26 overlaps a gate lone (GL), the gate line (GL) and the common electrode 14 are electrically shorted by the conductive ball 25 so as to reduce production yield.